AB0951 Entheseal involvement in healthy subjects: What can lower limb ultrasonography tell us?
Authors: S. Boussaid, R. Ben Aissa, S. Rekik, S. Jemmali, S. Rahmouni, H. Ajlani, H. Srairi Sahli, M. Elleuch
Journal: Annals of the Rheumatic Diseases (2022)

Background Over the past few years, ultrasonography (US) has been a very useful tool in the detection of subclinical enthesopathy especially in spondyloarthritis patients. However, could US entheseal involvement detection by US in healthy subjects be predictive of evolution to an inflammatory rheumatic disease? Objectives To identify by US the prevalence of entheseal abnormalities at the lower limb of healthy subjects and associated risk factors. Methods US assessment was performed on 400 entheses of 40 healthy volunteer subjects along with clinical examination. Exclusion criteria: Enthesitis on the physical examination, personal of family history of inflammatory rheumatic disease and previous surgery or procedural interventions in the knees and/or ankles. Quadriceps, patellar and calcaneal tendons, and plantar fascia entheses were scanned. Depending on lesion type, inflammation (thickening, hypoechogenecity, bursitis and Doppler signal) and chronic damage (calcifications, enthesophytes and erosions) scores (0= absent, 1=present) were calculated per entheseal site and per participant. Total score was obtained by adding these two scores. Data about age, gender, body mass index (BMI) and physical activity according to the short form of the International Physical Activity Questionnaire score (IPAQ-SF) were collected. Results The mean age of participants was 52.3±14.83 [20-78] and the ratio of males to females was 3:2. Fourteen participants had US subclinical enthesopathy (35%). Among 400 scanned entheses, thickening was the most frequent inflammatory lesion observed in 4 % (n=16) of the entheses, followed by hypoechogenecity (0.5 %, n=2). Enthesophytes were the most frequent chronic damage lesions detected in 1.25% (n=5) of the entheses followed by erosions (0.5%, n=2). The highest total US scores per entheseal site were observed at the calcaneal enthesis [mean (SD) 0.27(0.59)], followed by plantar fascia [0.18(0.50)] and distal patellar tendon origins [0.10 (0.37)]. Age was not associated to higher scores (total, inflammation, chronic damage; p=0.339, p=0.412, p=0.531). Female participants had higher inflammation scores than males (mean inflammation scores (SD) 0.69 (1.44) versus 0.39 (0.71), p=0.044). The BMI was correlated to higher inflammation score (p=0.020, r=0.368) but not to chronic damage nor to total scores (p=0.478, p=0.104). Intense physical activity was associated to higher chronic damage score comparing to moderate physical activity (mean chronic damage scores (SD) 0.30(0.67) versus 0.003(0.00), p=0.058) and to low physical activity (mean chronic damage scores (SD) 0.30(0.67) versus 0.0018(0.00), p=0.043). No association between physical activity and inflammation score had been observed. Conclusion Our study demonstrates that US changes within the enthesis are associated with higher BMI and physical activity. These results support the effect of biomechanical forces on the entheses that should be considered when differentiating by US pathological from healthy entheses. Disclosure of Interests None declared